This sticky thread lists known issues and breaking changes introduced in the UI for ASP.NET AJAX releases.

• Q3 2011 (Version number: 2011.3.1115)
• Q1 2013 (Version number: 2013.1.220)
• Q2 2013 (Version number: 2013.2.611)
• Q2 2013 SP1 (Version number: 2013.2.717)
• Q3 2013 (Version number: 2013.3.1015)
• Q1 2014 (Version number: 2014.1.225)
• Q2 2014 (Version number: 2014.2.618)
• Q3 2014 (Version number: 2014.3.1024)
• Q1 2015 (Version number: 2015.1.225)
• Q2 2015 (Version number 2015.1.623)
  
• Q2 2015 SP1 (Version number: 2015.2.729)
• Q3 2015 SP1 (Version number: 2015.3.1111)
• Q1 2016 (Version number: 2016.1.113)
• Q1 2016 SP1 (Version number: 2016.1.225)
• R2 2016 (Version number: 2016.2.504)
• R2 2016 SP1 (Version number: 2016.2.607)
• R3 2016 (Version number: 2016.3.914)
• R3 2016 SP1 (Version number: 2016.3.1018) 
• R1 2017 (Version number: 2017.1.118)
• R1 2017 SP1 (Version number: 2017.1.228)
• R2 2017 (Version number: 2017.2.503)
• R2 2017 SP2 (Version number: 2017.2.711)
• R3 2017 (Version number: 2017.3.913)
• R1 2018 (Version number: 2018.1.117)
• R2 2018 (Version number: 2018.2.516)
• R2 2018 SP1 (Version number: 2018.2.710)
• R3 2018 (Version number 2018.3.910)
• R1 2019 (Version number: 2019.1.115)
• R3 2019 (Version number: 2019.3.916)
• R1 2020 (Version number: 2020.1.114)
• R3 2020 SP1 (Version number: 2020.3.1021)
• R1 2021 SP1 (Version number: 2021.1.224)
• R2 2021 (Version number: 2021.2.511)
• R2 2021 SP1 (Version number: 2021.2.616)
• R3 2021 (Version number: 2021.3.914)
• R3 2021 SP1 (Version number: 2021.3.1111)
• R2 2022 SP1 (Version number: 2022.2.622)
• R3 2022 (Version number: 2022.3.913)
• R1 2023 (Version number: 2023.1.314)
• 2024 Q1 (Version number: 2024.1.131)
• 2024 Q3 (Version number: 2024.3.805)
• 2024 Q4 (Version number: 2024.4.1113)
• 2024 Q4 (Version number: 2024.4.1114)
• 2025 Q1 (Version number: 2025.1.211)
• 2025 Q2 (Version number: 2025.2.520)
• 2025 Q3 (Version number: 2025.3.825)
• 2025 Q4 (Version number: 2025.4.1111)
• 2025 Q4 (Version number: 2025.4.1321)
  

Q3 2011 (Version number: 2011.3.1115)

Problem: When adding items to OData-enabled controls (RadMenu, RadTreeView, RadListBox, RadComboBox) through design time erroneous markup is applied to the control:

<telerik:RadListBox runat="server" ID="RadListBox1">
    <Items>
    </Items>
    <WebServiceSettings>
        <ODataSettings InitialContainerName="">
        </ODataSettings>
    </WebServiceSettings>
</telerik:RadListBox>

Please note the added ODataSettings section. It will cause JavaScript errors on the page.

02 Feb to 09 Feb 2026: highlights of the new online resources that we published last week.

Article: https://www.telerik.com/products/aspnet-ajax/documentation/ai/troubleshooting
Summary: This guide helps you diagnose and fix issues when wiring Telerik UI for ASP.NET AJAX AI integration to OpenAI or Azure OpenAI. It covers common causes—invalid or missing API keys, incorrect base URL or api-version, using model names instead of Azure deployment names, 401/403/404/429 responses, TLS/firewall/CORS problems, and missing ScriptManager/resources—and shows how to verify web.config/code-behind settings, route calls through a server-side proxy, enable provider logging, and test requests independently. Use the checklists to validate payloads and model capabilities, handle timeouts and rate limits with retry/backoff, and confirm the controls are correctly initialized on the page.

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10 Nov to 17 Nov 2025: highlights of the new online resources that we published last week.

Summary: Learn how to collapse parent task nodes in Telerik RadGantt for ASP.NET AJAX using the JavaScript client-side API. You’ll see how to collapse all rows on initialization and programmatically toggle a task’s expanded state, so you can start with a compact Gantt and control the hierarchy on demand.

Article: https://www.telerik.com/products/aspnet-ajax/documentation/knowledge-base/autocompletebox-html-encoding-items
Summary: Learn how to control HTML encoding in the RadAutoCompleteBox for ASP.NET AJAX. You’ll encode entry/item text (e.g., via HttpUtility.HtmlEncode) to prevent XSS, and use item/token templates to render intended HTML when you need markup in the dropdown or tokens.

Article: https://www.telerik.com/products/aspnet-ajax/documentation/knowledge-base/grid-reorder-columns-with-keyboard-shortcut
Summary: This article explains how to implement keyboard-based column reordering in Telerik ASP.NET AJAX RadGrid. You enable client-side reordering, hook a keydown handler to move the focused header left or right via the RadGrid client-side API, and optionally persist the new order by setting the columns’ OrderIndex on the server.

Article: https://www.telerik.com/products/aspnet-ajax/documentation/knowledge-base/retrieve-visible-columns-radgrid-aspnet-ajax
Summary: This article shows how to retrieve the currently visible columns in a Telerik RadGrid for ASP.NET AJAX at runtime. It covers server-side enumeration via MasterTableView.RenderColumns (or filtering Columns by Visible and Display) and a client-side approach using masterTableView.get_columns() with column.get_visible()/get_display(), including considerations for columns hidden via the ColumnMenu and built-in utility columns.

Article: https://www.telerik.com/products/aspnet-ajax/documentation/knowledge-base/grid-scrolling-with-frozen-columns-with-mousepad
Summary: This article shows how to make two‑finger touchpad (mousepad) scrolling work correctly in the ASP.NET AJAX RadGrid when Frozen Columns are enabled. You’ll capture wheel/touchpad events over the frozen area and forward the delta to the grid’s scrollable container so horizontal and vertical scrolling stay synchronized, with a concise JavaScript example and guidance on wiring it on grid load.

Article: https://www.telerik.com/products/aspnet-ajax/documentation/knowledge-base/autocompletebox-disabling-dynamically-added-tokens-server-side
Summary: Learn how to disable dynamically added tokens in the ASP.NET AJAX RadAutoCompleteBox on the server side. You add entries in code-behind and mark them non-removable, then use a TokenTemplate and CSS to render them disabled so users cannot delete or interact with those tokens, while leaving user-added tokens unaffected.

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05 Nov to 10 Nov 2025: highlights of the new online resources that we published last week.

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29 Oct to 05 Nov 2025: highlights of the new online resources that we published last week.

Summary: Use the SpeechToTextButton control in Telerik UI for ASP.NET AJAX to capture microphone input and insert recognized text into a specified input or textarea using the browser’s Web Speech API. The overview shows how to configure the target element and recognition settings (language/culture, interim/continuous results), lists HTTPS/permission and browser support requirements (e.g., Chrome/Edge), and details the server- and client-side API and events (start, result, end, error) so you can manage the recognition lifecycle in JavaScript.

Article: https://www.telerik.com/products/aspnet-ajax/documentation/controls/speechtotextbutton/appearance
Summary: This article shows you how to style the ASP.NET AJAX SpeechToTextButton using built‑in skins and custom CSS, including setting the Skin property, toggling EnableEmbeddedSkins/EnableEmbeddedBaseStylesheet, and applying a CssClass. It also covers choosing a RenderMode (Classic or Lightweight) and identifying the control’s HTML/CSS hooks so you can create a custom skin and adjust size, colors, and visual states.

Article: https://www.telerik.com/products/aspnet-ajax/documentation/controls/speechtotextbutton/getting-started
Summary: This guide shows you how to add and configure the SpeechToTextButton in Telerik UI for ASP.NET AJAX to capture microphone input and insert recognized text into a target input (e.g., ASP.NET TextBox or RadTextBox). You’ll register the control, add the markup, associate it with the target input, configure recognition language/options, and wire client-side events for start/stop, results, and errors. It also covers browser and security requirements for the Web Speech API (HTTPS origin and microphone permissions) and provides a minimal working example to validate your setup.

Article: https://www.telerik.com/products/aspnet-ajax/documentation/controls/speechtotextbutton/client-side-programming/enums
Summary: This article lists the client-side enums for the ASP.NET AJAX SpeechToTextButton control and explains the meaning of each value and where it’s used in the control’s JavaScript API. Use these enums in your event handlers and custom logic to check recognition state, handle errors and permission changes, and avoid magic strings or numbers. The enums are available on the client side (Telerik.Web.UI) for consistent integration with SpeechToTextButton.

Article: https://www.telerik.com/products/aspnet-ajax/documentation/controls/speechtotextbutton/server-side-programming/enums
Summary: This article documents the server-side enumerations used by the Telerik UI for ASP.NET AJAX SpeechToTextButton. It lists each enum and its members, explains where they apply in the control’s API, and how they affect behavior and appearance so you can set them correctly in markup or code-behind (C#/VB.NET). Use it as a reference when configuring the control via server-side code.

Article: https://www.telerik.com/products/aspnet-ajax/documentation/controls/speechtotextbutton/client-side-programming/events
Summary: Handle the ASP.NET AJAX SpeechToTextButton client-side events in JavaScript to manage recognition lifecycle, receive result notifications, and handle errors. The article shows how to subscribe via the control’s OnClient* properties or programmatically through the client-side object’s add/remove event methods, and details the event arguments you’ll use to access recognition data and status. Use these hooks to capture interim and final transcripts, update UI state, and control when recognition starts, stops, or is canceled from your application code.

Article: https://www.telerik.com/products/aspnet-ajax/documentation/controls/speechtotextbutton/client-side-programming/overview
Summary: Learn how to get the RadSpeechToTextButton client-side instance in ASP.NET AJAX and use its JavaScript API to start/stop speech recognition, handle results and errors, and update input elements. The article summarizes the control’s client-side events, methods, and properties so you can wire up event handlers and control recognition from JavaScript.

Article: https://www.telerik.com/products/aspnet-ajax/documentation/controls/speechtotextbutton/server-side-programming/overview
Summary: Learn how to use the RadSpeechToTextButton server-side in Telerik UI for ASP.NET AJAX: its server-side properties, methods, and events, and how they interact with the ASP.NET Web Forms page lifecycle. Configure the control in code-behind, handle postbacks, and access the recognized text (e.g., via the target input or control state) for validation and processing.

Article: https://www.telerik.com/products/aspnet-ajax/documentation/knowledge-base/asyncupload-display-pdf-preview-file-selection
Summary: Learn how to show a client-side PDF preview immediately after file selection in ASP.NET AJAX using RadAsyncUpload, without uploading to the server. You handle OnClientFileSelected, get the selected File from the underlying input, validate it as a PDF, and render it in an iframe/object or RadPdfViewer via URL.createObjectURL or FileReader, with notes on multiple files and revoking object URLs.

Article: https://www.telerik.com/products/aspnet-ajax/documentation/controls/speechtotextbutton/client-side-programming/properties
Summary: This article documents the client-side properties of the Telerik ASP.NET AJAX SpeechToTextButton and shows how to access them through its JavaScript object ($find) using the standard get_/set_ pattern. You will learn how to read and update behavior, state, and configuration at runtime (for example, enable/disable, target control, and recognition state) so you can integrate speech-to-text into your forms without postbacks.

Feel free to check them out and share your thoughts!

The Telerik Team

When I run my project I'm getting this error

Could not load file or assembly 'Telerik.Web.UI' or one of its dependencies. The located assembly's manifest definition does not match the assembly reference. (Exception from HRESULT: 0x80131040)

In my web.config I checked that the version in the web.config is the same as the version I'm using in references

<assemblyIdentity name="Telerik.Web.UI" publicKeyToken="121fae78165ba3d4" culture="neutral" />
        <bindingRedirect oldVersion="0.0.0.0-2020.2.617.45" newVersion="2020.2.617.45" />

Hi , 

I’m working on aligning the loading dropdown that renders under rcbSlide with the width of the RadComboBox, even when an additional icon is present. Since rcbSlide resides outside the RadComboBox container, I need guidance on how to ensure the dropdown inherits or matches the RadComboBox width consistently.

I have a simple TreeView

    <telerik:RadTreeView ID="radTreeViewIndex" runat="server">
                    </telerik:RadTreeView>

That I am databinding on the page load.

My query returns heirarchical records such as the following

SPOP   TheKey     SYear     Norder

Null        A             Adult          4000
Null        P             Pediatric    3000
A            A2022     2022          2500
A            A2021      2021         2500
A           A2020      2020        2500
P            P2022     2022          2000
P            P2021      2021         2000
P           P2020      2020        2000

On the page load, I call the Oracle query, get back a cursor and construct the treeview by binding a data table to it

        DataTable dt1 =
            new DataTable();
        da1.Fill(dt1);
        RadTreeView radTreeViewIndex = (RadTreeView)FindControl("radTreeViewIndex");
        radTreeViewIndex.NodeDataBound += new RadTreeViewEventHandler(radTVI_click);
        radTreeViewIndex.DataFieldParentID = "SPOP";
        radTreeViewIndex.DataFieldID = "theKey";
        radTreeViewIndex.DataTextField = "sYear";
        radTreeViewIndex.DataValueField = "sYear";

        radTreeViewIndex.DataSource = dt1;
        radTreeViewIndex.DataBind();

The tree expanded would look like

> Adult

      - 2022 

     -  2021

     -  2020

> Pediatric

      - 2022 

     -  2021

     -  2020

The databinding and expanding/collapsing is working fine

That I am trying to now do and figure out how best to do is to navigate and load a grid based upon the click of a year

So clicking on Adult or Pediatric Nodes would only expand or collapse the tree
Clicking on the Year node would then call an event that would pass in the population and the year and then load that grid (to the right of the tree)  So for clicking on (Adult > 2021 ) node - was thinking navigating back to the page witth these values set, the tree expanded to show the selected node and the grid populated to display the records for population = adult and year = 2021

I was thinking I would add the event to the NodeDataBound

    protected void radTVI_click(object sender, RadTreeNodeEventArgs e)
    {
        if (string.IsNullOrEmpty(e.Node.NavigateUrl))
            e.Node.Attributes["onclick"] = "return Redirect(https://myjunkurl.com);";

    }

And then work with it to basically ignore or only have expand or collapse on the clicks of Adult or Pediatric but otherwise generate the URL to call the page and pass in the SPop and Year to then load the tree and grid.

Hi The following Web resource is not loading with the latest telerik version 2024.****. and affecting pagination.  Can you please help if there is any css or C# code that may affect. 

The application is built on asp.net 4.8 webforms.  Also could you kindly treat it as high priority as its impacting clients.  

Issue :  The height and space margins are varying. 

Kindly let us know if you need further details 

Best Regards, 

Sunil Shankar S R

I am trying to figure out how to accomplish this.  I am not sure if the RadGrid is best use

I have a data query that will return one or more records

Example - data returned may look like

UserID, User Full Name, User Status, Hire Date, Manager Name, Location, Skill Set, Last Review

And I want to format it as

Record 1

Row - User ID, User Full Name, User Status, Hire Date, Manager Name

Row - Location, Skill Set, Last Review

Next Record

Row - User ID, User Full Name, User Status, Hire Date, Manager Name

Row - Location, Skill Set, Last Review

Etc. 

I no problem filling data adapter, filling data table and then binding to grid in single row to record, but setting up multiple rows per record I am struggling. 

Thanks

Hello

I have a page that is ajaxed using Ajax Manager.  There is a RadWindow on the page which uses navigateurl rather than contenttemplate to show a page within the site (so not an external URL)

That page also has AjaxManager on it.  When an ajaxed field within the window is changed the page does a partial postback correctly (and updates whatever it needs to do on itself) however the scroll position of the parent page scrolls to the top.

How do I stop that from happening?

I note that I am using this to scroll back to the window on window load because on opening the window it would scroll to the top as well

  function fnRadWindowPageLoad() {
                if (modalPopUpScrollPositionObj != null)
                    window.scrollTo(modalPopUpScrollPositionObj.XCoordinate(), modalPopUpScrollPositionObj.YCoordinate());
            }

I'm using this to open the window in the code behind, after I've done some processing

Hi sir

     I use RadAjaxManager in master page  i call the RadAjaxManager in master.js file. in Grid itemdatabound call the function

if (gridid.toString().toLowerCase().indexOf("explorergrid") >= 0) {
    $("#ContentPlaceHolder1_ExplorerGridSelectedIndexHidden").val(index);
    var ajaxManager = $find('ctl00_RadAjaxManager1');
    ajaxManager.ajaxRequestWithTarget('ctl00$ContentPlaceHolder1$explorerGridViewLink', '');
}

when click the grid i got the error in png